Hazardous Materials Foam Practices

FOAM Introduction Operations trained responders should understand the characteristics of and be familiar with the applicability of appropriate foams The textbook does not have a section on foam.

FOAM Foam is a stable aggregation of small bubbles of lower density than water or oil, and shows a tenacious quality for covering horizontal surfaces.

FOAM Uses of foam / How it works Smothers - Prevents air and flammable vapors from combining Cools - lowers the fuel surface temperature Suppresses vapors - prevents release of flammable vapors Separates - intervenes between the fuel and the fire Reference these foam actions to how it works with respect to the fire tetrahedron.

FOAM Types of flammable / combustible materials Non-polar (Hydrocarbon) - liquid that is not miscible in water Polar solvent (Alcohol) - liquid that is soluble with water Non-polar (hydrocarbons) are a by- product of crude oil or have been extracted from vegetable fiber. Not Soluble: Product does not mix with water. Examples: Gasoline, motor oil, vegetable oil, animal fat. Polar solvents are products of distillation or have been synthetically manufactured Miscible: will mix with water Polar fuels have an attraction for water, foam is +94% water so these products are very destructive to normal foams Specially designed foams must be used.

FOAM Foam Terms Foam Concentrate Foam Solution Expansion Finished Foam Raw foam liquid before its mixed with water and air Foam Solution the mixture of foam and water before air is added Expansion the ratio of final foam volume to original foam volume Finished Foam the completed product after foam concentrate, water, air, and mechanical agitation have been combined These terms are used in the next slide

FOAM Elements necessary for high quality foam: 1. Foam concentrate 2. Water 3. Air 4. Mechanical agitation (aeration) How finished foam is made: Concentrate (out of container) is inducted into the hose (mixed with water) to form solution. The solution is moved through a nozzle which adds air to the the solution. The amount of air which is added will effect the expansion ratio. This product after the addition of the air is the finished foam.

FOAM Foam Equipment Metering devices In-line eductor Bypass eductor Self educting Fixed apparatus foam systems These are the different devices used to make foam solution. In-line eductor and Bypass eductor are used on hand lines. Bypass educators allow for the suction in the pick-up tube to be shut off and just water can be flowed. Self educting nozzles have a built in eductor which has no friction loss. The down side is the pickup tube is also at the nozzle. There are many different apparatus foam system. These systems would include having foam as well as water tanks.

Foam Equipment Handheld foam nozzles Foam Nozzle and Eductor Master stream device 250 – 500 gpm Each of these pictures will come up individually. The bigger one that I have to retrieve the picture for is >500 gpm Fixed Apparatus Foam Device

Foam Eductors In From Pump (200psi) Out to nozzle (130psi) 70 psi of friction loss for eductor This slide is animated by mouse click to show how foam is made. When educting foam the eductor GPM and the nozzle GPM must match for proper foam production. When educting foam the nozzle must be completely open. The goal is to have proper pressure at the nozzle. With 200 psi coming in from pump, the water moves across the pickup tube opening creating suction (venturi effect). This picks up foam concentrate and mixes it with the water creating foam solution. The eductor creates about 70 psi of friction loss. Leaving 100psi for the nozzle and 30 psi for the hose friction loss. Foam concentrate

FOAM Foam Equipment (continued) Nozzles Non air aspirating hand line nozzles Air aspirating hand line nozzles Non air aspirating monitor nozzles Hand line nozzle clamp–on device Air aspirating nozzles will give the best quality foam.

Hand line nozzle and eductor Handline nozzle clamp-on device Foam Non air aspirating Hand line nozzle and eductor Non air aspirating Monitor nozzle Air aspirating Hand line nozzle Handline nozzle clamp-on device

FOAM Foam Equipment The four D’s of making foam Dirty Devices Don’t Deliver Old dried out foam concentrate in the pick-up tube and the eductor can block the flow of concentrate and diminish or eliminate the venturi effect. The most common failure is the ball valve.

FOAM The four C’s of making foam Compatible Components Create Competence Trouble shooting: Make sure components are matched 95 gpm nozzle with a 95 gpm eductor etc. Flowing correct percentage of foam concentrate. Foam concentrate is compatible with product. Foam nozzle completely open. Consider locked orifices and dirty screens.

Types of Foam Class A Foam Class B Foam Specialty Foam Emulsifiers Used on Class A materials as wetting agent Class B Foam Used on Class B materials broken into 2 categories Non-Polar and Polar solvents Specialty Foam Manufactured for specific products where traditional foam will not work. Emulsifiers Breakdown the product Class A foams work by lowering the water’s viscosity. Used in wild land firefighting. Not widely used in structural firefighting (similar to detergents). Class B foam is the most common found in the fire service. Specialty foams such as the ones made for Acids. Emulsifiers work by breaking down the carbon chain and encapsulating the product. Some of these products are rated as Class A / Class B foams. These products stop the vapor production, burn-back, and reignition by this process.

FOAM Types of Foam Protein Fluoroprotein Film Forming Fluoroprotein (FFFP) Aqueous Film Forming Foam (AFFF) Alcohol Resistant (ARC /ATC) High Expansion Overview slide for following slides.

FOAM Protein Foam Made from protein based materials Heat strengthens the foam bubbles Suitable only for non polar hydrocarbons Used at 3% and 6% Must use an air-aspirating nozzle. Not used much any more. Best choice for non-ignited spills.

FOAM Fluoroprotein Foam Made by mixing protein agents with fluorinated surfactants Sheds fuel (subsurface injections) Has good water retention Excellent heat and burn-back resistance Compatible with most dry chemicals Superior sealing power

FOAM Film Forming Fluoroprotein Foam (FFFP) Based on fluoroprotein technology and aqueous film forming capabilities Can be used for subsurface injection Incorporates fast knockdown and long lasting resistance Compatible with most dry chemicals

FOAM Aqueous Film Forming Foam (AFFF) Describes action rather than product makeup Floats in very thin layers over liquid which spreads quickly over flammable fuels Water drainage from bubbles slides out from foam mass Knockdown 2-4 times greater than protein based foams Self healing See next slide for drawing

AFFF FOAM Non-Polar Solvent Air Foam Blanket Aqueous Film (light water) Foam Blanket Non-Polar Solvent As the foam is applied a layer of Aqueous film drains out of foam covering the fuel ahead of the blanket. This aqueous film is also known as “light water” . This film along with the blanket smother the fire by creating a barrier between the fuel and the air. It is because of the film that AFFF has such a great self-healing property

FOAM Alcohol Resistant / Polar Solvent Universal Foam Concentrate Protein or synthetic based Used on polar and non polar solvents Creates a “membrane” rather than a film over fuel 3% for non polar solvents 6% for polar solvents Non polar solvent : gasoline Polar Solvent : alcohol Has a polymer in the foam which is pulled out by the product forming a thin polymer membrane over the spill. Will only self heal if there is polymer still available in foam. Both the AFFF and FFFP ATC (Alcohol Treated Concentrate)/ARC (Alcohol Restive Concentrate) can be used on both polar and non-polar materials.

Alcohol Resistive Foam Air Polymer Film Foam Blanket Polar Solvent As the foam is applied a polymer layer is drawn out of the foam creating a barrier between the foam and the polar solvent. This polymer film protects the water in the foam from the polar solvent thus slowing the breakdown of the foam blanket. The film will only self-heal if there is polymer left in the foam blanket. If not more foam needs to be applied.

FOAM Hazardous Materials Foam Concentrates Special purpose foams Use on pesticide fires Suppress acid vapors Stabilized Stabilized foam: After flowing the foam it will set-up as a jello-like substance. As it dries out, it can be rewet.

Foam High Expansion Foam Detergent based 150:1 expansion ratio Low water contact Suppress fires in concealed spaces Used for basement fires. Fills the space with foam smothering the fire.

FOAM Application of Foam Guidelines Select proper concentrate Compatible nozzle and eductor Sufficient foam concentrate on hand prior to beginning operation Work from uphill / upwind side Never plunge stream into fuel Overview of foam application techniques to be discussed in next slides.

FOAM Application Techniques: 1. Lob / Cascade / Raindown 2. Bank / Bounce 3. Roll 4. Subsurface Injection (Fluoroprotein) These techniques practiced in the practical exercise. (exception Subsurface injection)

1. Lob / Cascade / Rain down

2. Bank / Bounce

3. Roll

Subsurface Injection Foam Solution Foam Concentrate The foam in injected in the tank. The foam will float to the surface shedding any product which will then cover the surface of the tank. This is the most effective way to extinguish a tank fire.

Subsurface Injection Foam Solution Foam Concentrate The foam in injected in the tank. The foam will float to the surface shedding any product which will then cover the surface of the tank. This is the most effective way to extinguish a tank fire.

Foam Application Techniques Foam Activity Foam Application Techniques